« ΠροηγούμενηΣυνέχεια »
salts of silver. It is generally prepared by adding the metal It is decomposed by chlorides and sulphurets, in the same
One equivalent of sulphurous acid . 32 rhombic prism. Nitrate of silver has a bitter metallic taste,
One equivalent of oxide of silver 116 is soluble in about its own weight of water at 60°, and in half its weight of boiling water; the solution is neutral to litmus
148 paper. Cold alcohol dissolves only a little of this salt, but Hyposulphate of Silver is prepared by digesting carbonato when boiling takes up a considerable quantity of it, the of silver in hyposulphuric acid." It crystallizes in prisms. greater part of which separates on cooling.
Hyposulphite of Silver.-It is obtained by gradually By the action of light, especially when in contact with adding a weak solution of nitrate of silver to a dilute one of organic matter, nitrate of silver is rendered of a dark hyposulphite of soda. It is a precipitate of a grey colour, colour, and is then insoluble in water. When moderately and the supernatant liquor is stated by Herschel, who has heated, nitrate of silver fuses, and being then cast in a mould particularly examined this salt, to be remarkably sweet, in small cylindrical sticks, it constitutes the argenti without any metallic flavour. It is also formed when nitras of the Pharmacopeia, commonly called lunar caustic; chloride of silver is dissolved in a hyposulphite. This salt if the heat applied be too great, the salt is decomposed, is very liable to spontaneous decomposition, and becomes oxide of silver being left, which, if still more strongly heated, black owing to the formation of sulphuret of silver. The gives metallic silver. When sulphur, phosphorus, or char- hyposulphites have been advantageously employed in recoal is inixed with nitrate of silver, and struck on an anvil, moving of the unchanged salt of silver in photogenic drawdetonation ensues, and metallic silver is obtained; the ings. Hyposulphite of silver is composed of experiment should be made on very small quantities, One equivalent of hyposulphurous acid 48 Nitrate of silver is decomposed by simply placing charcoal One equivalent of oxide of silver 116 or phosphorus in its solution, metallic silver being deposited in the crystalline state ; the same effect is produced by
164 several metals, and more especially copper, which is used in Phosphate of Silver. This is prepared by adding a solusilver-refining for precipitating the silver from the nitrate tion of the common neutral phosphate of soda to one of in a pure state.
nitrate of silver; a yellow precipitate is formed, which is Chlorate of Silver may be obtained by dissolving proto quickly discoloured by exposure to light; becomes browny oxide of silver in chloric acid; the solution yields small when heated, but regains its yellow tint on cooling ; and rhombic crystals, which are soluble in four parts of water at when strongly heated, it melts. It is soluble in nitric and 60°. This salt is not applied to any use.
phosphoric acid. It is a subsesquiphosphate, composed of Nitrate of silver is decomposed by sulphuric and phos
1 equivalent of phosphoric acid 36 phoric acids, and their soluble salts, sulphate and phosphate
1 equivalent of oxide of silver . 174 of silver, are thrown down. Potash and soda and the alkaline earths precipitate protoxide of silver; ammonia pro
210 duces the same effect, but when added in excess, redissolves Pyrophosphate of Silver is obtained by heating neutral the oxide at first precipitated. Hydrosulphuric acid, hydro- phosphate of soda so as to expel its water, and adding a sosulphates, and soluble sulphurets occasion the formation and lution of it to one of nitrate of silver. This precipitate is of precipitation of black sulphuret of silver.
a white colour. Like the preceding, it is composed of one Chlorine partially, and soluble chlorides and hydrochloric equivalent each of acid and base. acid and hydrochlorates, perfectly, decompose nitrate of silver, We shall mention the properties of a few of the salts chloride of silver being precipitated. It is on this account formed by the combination of the vegetable acids with oxide that nitrate of silver is employed, and with great accuracy, in of silver. both qualitative and quantitative analyses.
Acetate of Silver.-It may be prepared by dissolving oxide Nitrate of silver is composed of
of silver in acetic acid, or, as it is a salt of slight solubility, One equivalent of nitric acid
in water, by decomposing nitrate of silver with acetate of One equivalent of protoxide of silver 116
soda, when it is thrown down as a crystalline flocculent
precipitate. It is a colourless salt, sparingly soluble in Equivalent: 170
water, and decomposed at a red heat. It is occasionally Besides the uses already named, nitrate of silver is em used as a chemical re-agent. It consists of ployed by precipitation with carbonate of soda, &c, for
One equivalent of acetic acid
51 writing on linen; it is commonly called indelible ink.
One equivalent of oxide of silver
116 Carbonate of Silver is prepared by adding a solution of carbonate of potash, or of soda, to one of nitrate of silver.
167 It is a white substance, insoluble in water, but dissolved by Benzoate of Silver may be obtained either by digesting ammonia, and decomposed by acids ; it is blackened by ex moist oxide of silver in a solution of benzoic acid, or by posure to light, and readily decomposed by heat. It is pro- adding a benzoate to it. It is a white anhydrous combably composed of
Citrate of Silver is formed by adding a citrate to nitrate of
silver. It is an insoluble white powder, which blackens by
exposure to light, and detonates slightly when heated. It Equivalent
is composed of Sulphate of Silver.—This salt may be formed by boiling
One equivalent of citric acid . 56 finely divided silver in strong sulphuric acid, by dissolving
One equivalent of oxide of silver 116 the protoxide in dilute sulphuric acid, or by adding a solution of sulphate of soda to one of nitrate of silver, when it
172 is thrown down as a crystalline precipitate.
Oxalate of Silver is precipitated when oxalic acid or an Sulphate of silver is a colourless salt, soluble in about 90 oxalate is added to nitrate of silver. It is insoluble in parts of water at 60°; a saturated boiling solution deposits water, white, and rendered black by exposure to light. It Crystals on cooling, which are prismatic and anhydrous; detonates slightly when struck on an anvil. It is soluble in when strongly heated, the acid is expelled, and metallic sil- nitric acid, and decomposed by hydrochloric acid. It is ver remains. It is sometimes employed as a chemical re- probably composed of agent, and is composed of
One equivalent of oxalic acid
36 One equivaleni of sulphuric acid 40
One equivalent of oxide of silver
152 Equivalent 156
Cyanide of Silver is prepared by adding hydrocyanic acid
to a solution of nitrate of silver; the hydrogen of the acid They gire a white precipitate, insoluble in water or in uniting with the oxygen of the oxide of silver, water is dilute acids, but readily in ammonia, by chlorides and hyformed, and the cyanogen and silver combine, and form drochlorates; the precipitate becomes black by exposure to cyanide of silver, wbich is precipitated. It is colourless, in the light. soluble in water or solution of potash or soda, but readily Metallic silver is precipitated by copper and the solution taken up by ammonia. Nitric and sulphuric acid act but of protosulphate of iron; black sulphuret, by hydrosulphuric slightly upon it, unless concentrated and heated; hydro-acid and hydrosulphates. A yellow precipitate by arsenious chloric acid decomposes it, and hydrocyanic acid and chlo- acid and phosphate of soda; a red-brown, by arseniates; a ride of silver result, and this is one of the methods of pro- crimson, by chromates; and white, by the ferrocyanide of pocuring the last-mentioned acid, adopted in the London tassium. Pharmacopeia. It is decomposed by hydrosulphuric acid, With respect to the uses of silver it is scarcely requisite by which sulphuret of silver and hydrocyanic acid are ob- to say anything, as they are well known in iis applicatained. It is composed of
tion to coin and the formation of vessels of great beauty and One equivalent of cyanogen
durability. One equivalent of silver .
SILVÉR, PRODUCTION AND CONSUMPTION.
Silver-ores are found chiefly in veins which traverse the Equivalent
primary and the older of the secondary stratified rocks, but Ferrocyanide of Silver is obtained when ferrocyanide of especially the former; and also the unstratified rocks, such as potassium is added to nitrate of silver. It is a white insolu- granite and porphyry, which are associated with the above. ble substance.
Some of the richest mines in South America are situated in Cyanate of Silver is formed when cyanate of potash is primary strata ; also in limestone and in grauwacke, and in added to nitrate of silver. It is a white powder, slightly still more secondary strata. In some of the mines of Peru, and soluble in hot water, and also in ammonia. It blackens in those of Kongsberg in Norway and Freiburg in Saxony, when heated, and burns with deflagration, and there are silver has been discovered in masses weighing from 100 io produced di cyanide of silver, cyanic acid, carbonic acid, and 8001hs. In the mines of Europe the veins are numerous and
slender; in some of the mines in the Harz Mountains and in Fulminate of Silver. Fulminating Silver.—This very the Hungarian mines the veins occur in a small number of explosive compound is formed by dissolving 60 grains of spots, and are of considerable dimensions. In three of the silver in half an ounce of nitric acid of specific gravity 1.38; richest districts of Mexico there is only one principal vein, to the solution are to be added two ounces of alcohol of spe- which is worked in different places. One of ihese veins, in cific gravity 0.88, and the mixture is to be heated in a capa- the district of Guanaxualo, is from 130 to 148 feet wide, and cious flask; a white flocculent precipitate soon begins to it has been traced and worked to an extent of nearly eight appear, and when ebullition commences, the flask is to be miles. removed from the heat; the effervescence still continues, In Mexico there were 500 mining establishments, called and when it has ceased, the product is to be collected on a Reales, at the time of Humboldt's visit, and from 3000 to filter, washed with cold water, and dried at a temperature 4000 veins or masses were worked. The most common ores not exceeding 100° Fahrenheit.
are the sulphuret of silver, antimonial silver, and muriate Fulminate of silver is a greyish-white crystalline powder. of silver. It becomes darker by exposure to light; it dissolves in about The average richness of all the ores in Mexico is from 3 40 parts of boiling water, and separates, as the solution to 4 ounces per quintal of 102 lbs. In one of the Mexican cools, in minute crystals. In the quantity even of a half mines a working of one hundred feet in length yielded in six grain it detonates violently, either by the action of heat, months 432,274 lbs. troy of silver, equal in value to about electricity, strong sulphuric acid, or friction. When placed 1,000,0001. In Chili some of the mines yield only 8 oz. in on one tint, and slightly touched with another, explosion 5000 lbs. of ore; but in tlie rich mine of Copiapo, discovered also takes place. It has been known to detonate with great in 1832, the ore frequently contains 60 or 70 per cent. of silver. violence when a little has remained between a stopper and The average produce of the mines in Saxony is from three the neck of a bottle, on screwing in the stopper. It should to four ounces in the quintal. The lead-nines of Craven be preserved therefore in small portions, in paper, in a wide- in Yorkshire contained 230 ounces per ton; and those of mouthed corked vial. It is composed of
Cardiganshire, worked in the reign of Charles I., yielded One equivalent of fulminic acid 68
80 ounces. The average proportion of the lead-mines of Two equivalents of oxide of silver 232
the north of England is 12 ounces per ton. Even when
the proportion of silver is so low as eight ounces, or one Equivalent
grain per 1 lb., it has been found profitable to separate it. Alloys of Silver.—Little or nothing is known respecting The pure metal is separated from the ore by various prothe alloys of silver with the following metals:- Potassium, cesses; by mechanical division, roastings to separate the sodium, and the metals of the alkaline earths; manganese, sulphur and other volatile matter, and melting at different cadmium, nickel, uranium, tellurium, titanium, cerium, stages of purification, with the addition of fluxes of various chromium, and vanadium.
sorts. Refining is performed by amalgamation with quickIron and silver combine with difficulty. They separate silver, the two metals being afterwards separated by dison cooling, the iron retaining about one-eightieth of silver, tilling off the quicksilver. and the silver about one-thirtieth of iron. According to The produce of the Mexican mines averaged annually Faraday and Stodart, steel containing about one five-hun- 4,800,0001. from 1793 to 1803, of which nineteen-twentiethis dredth of silver forms a good alloy for cutting instruments. were silver. In the first ten years of the present century Iron and silver form a bluish-white granular alloy; tin and the average annual value was about 5,000,0001., the quansilver, a white, hard, brittle alloy. When cobalt and silver tity of pure silver annually produced in that time being are fused together, they separate during cooling, each re 1,440,650 troy lbs. The mines of Potosi in Peru are the taining a portion of the other. Lead and silver give a dull most famous in South America. [Porosi.] The produce brittle alloy; antimony and silver, a white brittle alloy; of the Chilian mines in 1832 was about 1,000,000 ounces. arsenic and silver form a grey, brittle, granular compound, At the commencement of the present century Humboldt containing about 14 per cent of the former metal. Bismuth estimated the annual produce of the silver-mines of Chili, and silver give a yellowish-white, brittle, lamellar alloy ; Peru, Buenos Ayres, and New Grenada, at nearly 700,000 lbs. molybdenum forms a compact, brittle, grey, granular com- troy, valued at 2,074,4761. sterling. pound with silver; and tungsten, a brown, slightly malleable The annual average of both gold and silver coined in the button; copper and silver readily combine, and the silver is different mints of Spanish America was estimated, in 1810, rendered harder by it without much deterioration of colour; at 8 millions sterling, namely, in Mexico 24 millions of dolthe standard silver of this country is composed of 11:10 silver lars ; Lima, 6 millions; Potosi, 44 millions ; Santa Fé and and 0-90 copper. Mercury and silver amalgamate readily, Santiago, each 14 million; and Popayan and Guatemala, and this compound is sometimes employed for plating, but nearly 1 million. The proportion of silver to gold coined at this operation is now being most advantageously carried on all these nts was stated as 30 to 1; the proportion of by precipitation by means of voltaic electricity,
silver to gold produced from all the American mines was as Properties of the Salts of Silver.—The solutions of the 62 to l; and from the mines of all countries as 52 to 1. salts of silver are recognised by the following, among other In a work published at Paris in 1807 by M. Brongniart, the properties which have been occasionally mentioned : value of the gold and silver brought annually into circulation
from all parts of the world was estimated at nearly 46 mil-, and the other extending the inquiry from 1809 to 1829, lions of dollars; of which 36 were from the mines of Spanish complete this part of the subject. The investigations of America, 4.4 from those of Portuguese America, and 54 from Humboldt, and the personal inquiries of Mr. H. G. Ward the mines of the Old World. "(Report of Bullion Com- (Mexico in 1827), with the scattered notices of other writers, mittee, 1810.)
are collected and arranged by Mr. Jacob, whose work must The most productive mines in Europe are those in Saxony, always be valuable for reference in all questions relating to Austria, Hungary, Norway, Russia, and Spain. The mines the history of prices. Several chapters of the work are dein Saxony have been worked since the tenth century. The voted to this topic in connection with the increased supply average annual produce of all the European mines in the of the precious metals after the discovery of America, and last twenty years of the eighteenth century did not exceed the rise of prices which occurred in Europe in the sixteenth 600,0001. in value. In the early part of the thirteenth cen- century. The gold and silver coin in Europe, in 1492, Mr. tury the mines of Schneeberg in Saxony are said to have Jacob'estimates at 34,000,0001., which was increased in the yielded 600,0001. annually; but taking the average of all course of the next 112 years by 138,000,0001., making the ihe mines of late years, the annual produce does not, ac total gold and silver currency in 1599, allowing for abrasion, cording to the estimate of Mr. Jacob, exceed 400,000 lbs., or &c., 172,000,0001. In book i., chapter xi., of the Wealth of 100.0004. in value. The mines of Chemnitz and Kremnitz Nations,' there is a ‘ Digression concerning the Variations in Hungary have been worked about a thousand years. in the Value of Silver during the course of the Four last Those of the Tyrol have long ceased to be productive. The Centuries.' mine of Kongsberg in Norway was probably the richest in The proportional value of gold to silver was 12 and 10 to 1 Europe during the middle of the last century. It yielded from the Anglo-Saxon times to the discovery of America. 649,270lbs. troy, value nearly 2,000,0001., in the forty it is at present 14.28 10 1. In antient Greece the proporyears from 1728 to 1768. The silver of Russia is obtained tion varied from 15 and 10 to 1, and in Rome from 12 and from the refining of stream gold found in the Ural Moun. 7 to 1. Herodotus (iii. 95) estimates it at 13 to 1. Since tains, and from lead-ores. Silver-mires were worked in the discovery of America the proportion throughout the Spain from a very early period by the Phænicians, Cartha- world has been 17 and 14 to 1. (Kelly's Cambist.) ginians, Ronians, and Moors; but they are now abandoned Mr. Jacob gives the amount of silver coined in eacb as unprofitable.
reign from the time of James I. :Native silver and several of the other varieties of the ores are met with in some of the Cornish copper-mines, and silver James I.
(22 years) 1,807,277 is extracted from the ore of English lead; but with these Charles I. and the exceptions, and very small quantities which are occasionally Commonwealth . (35 yea
9,776,544 found of this metal, silver cannot be considered as consti Charles II.
3,722,180 tuting one of the mineral treasures of the United Kingdom. James II.
( 4 years)
2,115,115* A vein of silver-ore and the sulphuret was worked in Stir William and Mary, lingshire during the latter part of the last century, and and William III. (12 years)
7,093,074 from 40,0007. to 50,0001. were obtained, when the vein was Anne
618,212 löst. In 1607 a silver-mine was worked in Linlithgowshire. George I.
(13 years) 233,045 The silver-mines of Asia have ceased to be very produc
(33 years) 304,360 tive in modern times. There are mines in Armenia, but George III. from none are known to exist in Persia, nor in any part of the
1760 to 1809
63,419 East India Company's possessions. Silver-mines are worked
1809 to 1820
(11 years) 6,933,346 in China ; and Mr. Davis remarks (Chinese) that the great quantities of silver brought to Lintin for many years past,
The last new silver coinage for the United Kingdom was to be exchanged for opium and exported to India, prove that commenced in 1816, since which time the quantity of silver there must be abundant sources in the empire. Silver is coined in each year has been as follows:
Years. not obtained in any part of Africa.
1816 Gold and silver appear to have been in request from the
1817 earliest ages. Abraham was rich in silver and in gold.
1831 He bought a field for a burial.place, for which he paid 400
1832 shekels of silver, delivered by weight, according to the
145 currency of the merchants.' (Genesis, xxii., 14-16.)
1821 Joseph, his great-grandson, was sold by his brethren for
432,775 twenty pieces of silver (Genesis, xxxviii., 29); and when
1836 aftewards they went to Egypt to purchase corn, they brought
497,719 • silver in their sacks' mouth.' (Genesis, xlv., 22.) In
1838 the book of Job (xlii., 11•12), we read of silrer passing
174,042 from hand to hand as money. The writer of that book
390,654 was acquainted with the fact that silver was found in veins
1828 and gold in particles, though the country in which he lived
16,288 did not produce the precious metals. It is said (1 Kings,
Total £11,108,265 x.) that in the days of Solomon silver was nothing ac The weight of silver coined, and the number and denocounted of, and that the king made silver to be as siones mination of each coin issued from 1816 to 1840 inclusive, in Jerusalem.' Darius Hystaspes, king of Persia, annually were as follows, according to a parliamentary paper (Sess. collected 9880 talents of silver, besides gold, as tribute from 1841):Asia and Africa ; subsequently tribute came in also from
Number, the islands of the Mediterranean and from Europe as far Crowns
140,141 1,849,905 462,476 west as Thessaly. Herodotus states (iii. 96) that the gold Half-crowns 1,190,876 31,438,434 3,929,804 and silver were melted and poured into earthen vessels,
Shillings 1,540,080 101,6 15,280 5,082,264 and that the earthen vessels were then removed, which left
441,852 58,324,595 1,458,114 the metal in a solid mass: when any was wanted, a piece
Fourpences. 52,140 10,325,320 177,062 was broken off as the occasion required. Silver was coined
Maunday money: at Rome 266 B.C., before gold had been so employed. (Coin.]
60,720 1,012 For further information on the production and uses of
892 the precious metals, the reader may refer to Mr. Jacob's
742 elaborate ‘History of the Consumption of the Precious
The seignorage, or the difference between the price at smelting Chapter x. is an inquiry into the production of which bullion is purchased and the mint price of the coin the precious meials during the middle ages, from the disso. at 58. 6d. an ounce, ainounted to 616,7471. on the abore. lution of the Western Empire to the discovery of America. The Maunday money is coined for the purpose of being Another chapter is on the produce of the mines at the epoch distributed by the Lord Almoner in Whitehall Chapel on of this discovery; also one from this period to the opening Maunday Thursday. of the mines of Potosi , in 1564; and two other chapters,
When silver is issued for coin, it is always alloyed with one on the produce of gold and silver from 1700 to 1809,
• Incluling £1,596,799 base inoney coined for Ireland,
copper : the maximum of hardness is produced by one-fifth | SILVER, Medical Properties of. Iu a purely metallic of copper. One lb. of standard silver of the English coin. state silver has no action on the animal frame, and the only age contains 11 oz. 2 dwts. of pure silver and 18 dwts. alloy, salt much used is the nitrate, terned also lunar caustic. or 925 parts of pure silver in 1000 parts of standard silver. This is always fused in proper moulds, from which it is [Money.) For purposes connected with the manufacture of turned out in the form of cylinders, about three inches long, various articles of use and ornament the alloy is greater. At and the eighth of an inch in diameter. They are at first Birmingham rolled sheets are made which do not contain white, but quickly become of a dark grey or black colour, more than 3 or 4 dwts. of silver to each Ib. of the inferior from combining with organic matter in the air. To prevent me:al
this the cylinders are generally wrapped up in blue paper. The rolling of silver in contact with the inferior metals is When nitrate of silver is brought in contact with any part performed by powerful Hatting-mills. A bar of copper is of the human frame, it causes first a white mark, which made quite smooth and clear on one of its surfaces, and is gradually changes to blue, purple, and at last to black. This then sprinkled over with glass of borax, and there is laid occurs more rapidly if moisture be present; and is owing to upon it a plate of fine silver, and the two are carefully bound a chemical combination of the metal with the albumen and together by wire. The mass is then exposed to a full red fibrin of the animal tissues. If the part be wetted, and the heat, which melts the borax and causes the silver to adhere caustic applied several times at short intervals, vesication to the copper. The ingot is now passed through a rolling- results. Nitrate of silver acts therefore locally as an irripress and formed into a plate, boih the silver and copper tant and corrosive. When taken internally in small doses extending uniformly during the whole process, at the con- for a considerable time, such as six or twelve months, it is clusion of which they are inseparably joined. The art of absorbed and deposited in various parts of the body, and silver-plating was introduced at Sheffield about the middle when it is deposited in the rete mucosum of the skin it of the last century. Another mode of plating is called 'sils causes discolorations, which in most cases prove permanent. vering,' when an amalgam of silver and mercury is well It lias been employed frequently withi success, but often rubbed upon the surface of the copper; by the application with failure, in the treatment of epilepsy, chorea, and some of heat the mercury is driven off, and the silver remains forms of angina pectoris, as well as morbid sensibility of behind, adhering firmly to the copper, and capable of being the stomach. Larger doses can be borne when it is admihighly polished.
nistered in the form of pill than in solution. The pills Mr. Jacob estimates the annual consumption of silver in should be made with mucilage and sugar, but not with the United Kingdom at 3,282,046 oz., valued at 820,521l. bread-crumb, as the common salt, or chloride of sodium, deThe consumption for watch-cases is about 506,000 oz. composes the nitrate and renders it inert. In cases of poiannually: 100,000, each weighing on an average 2 oz., are soning by nitrate of silver, common salt is a ready and stamped annually at the London Assay-office; 60,000, each effectual remedy. The liability of nitrate of silver to proweighing 2 oz., are stamped at Birmingham; and 80,000, of duce discolorations of the skin in persons taking it interthe same weight, are stamped at the other assay-offices in the nally constitutes a serious objection to its employment, and kingdom. About 900,000 oz. are used by coach-makers, there appears little necessity for giving it, since any case of harness-makers, and saddlers' ironmongers. In articles of epilepsy likely to be benefited by it will generally receive small size, such as thimbles, of which hundreds of thou- equal good from the use of oxide of zinc, without the risk sands are annually made; chains for watch-gnards, pencil- of stains or other inconvenience. It has been suggested cases, necks of smelling. boltjes, locks of pocket-books, in- that the use of nitric acid internally as well as externally strument cases, and portfolios, and small portions to handles may remove the discolorations; but it is better not to incur of penknives and razors, the silver used is under the the chance of causing them, than trust to the remote chanco weight which subjects it to the stamp.duty of 1s. 6d. an oz., of removing them by such an expedient. but a very considerable quantity of silver is employed in The external employment of this agent is not liable to these minor objects. Leaf-silver for gilding is made two any objection when used cautiously, while its advantages and a half times thinner than gold, and the gold-beaters are very great. It is the most powerful direct antiphlogistic require a considerable quantity of the metal for this pur- agent known. All subacute inflammations in any part to pose. Some articles are • washed' with silver. Mr. Jacob which it can be immediately applied will subside under its distributes the total consumption as follows:
influence. In intlammations not merely of the skin, but of That paying duty
1,275,316 oz. mucous membranes when they occur in parts which are That used in watch-cases
506,740 accessible, its influence is great, and speedily manifested. That used in plating
900,000 Many of the cases of croup which in an advanced stage are That for other minor purposes
500,000 unmanageable, begin in the back part of the throat (fauces),
and if these parts are freely touched with a pencil dipped in
3,282,046 a strong solution of nitrate of silver, the farther downward The value of the stock of silver in the hands of the ma progress of the inllammation may be arrested. The same nufacturers and dealers is estimated by the same authority treatment is applicable to the erythematous inflammation at 3,280,0001. The value of ornaments and utensils of the which frequently begins either externally, and spreads precious metals in Europe and America, if brought to the through the mouth or nose to the fauces, and thence down crucible, Mr. Jacob values at 400,000,0001., or one fourth the wsophagus, or originates in the fauces, leading to rery more than the value of the coined metais. The annual con- serious results. Erysipelatous inflammation occurring in sumption of gold and silver in Europe and America for or any part of the body may be effectually limited by nitrate namental purposes he states to be nearly 6,000,0001., that of of silver. For this purpose a complete circle should be Great Britain being valued at 2,457,0001. In M Culloch's formed round the in/lamed parl, but on the sound skin. * Dictionary of Commerce," it is stated that Mr. Jacob's cal. For this case the solid cylinder, moistened at the end, is culations are generally too high. Silver forms by far the best. The circle must be perfect, or the morbid action largest proportion of the value of domestic utensils in which may extend, escaping at the smallest breach. Chronic either of the two precious metals are used. In England the inflammation, and even ulceration of the eyes, may be regold currency is of much higher relative value than that moved by mitrate of silver applied in different forms. Old of silver (CURRENCY]; but in most other countries this is indolent ulcers are stimulated to a healthy action by its use; not the case. The coinage of silver and gold in France is and many cutaneous diseases removed by it. Recent burns estimated at 100,000,0001., a very large proportion of which have the severe pain often very much mitigated by it; but is of silver. Since the peace, the number of silversmiths it must not in any of these cases be applied to too large a and persons engaged in working silver and gold into articles surface at once, as ill effects have followed such a practice. of ornament and use has greatly increased on the Continent; To specify all the uses of nitrate of silver would be imposand the increase of the same class is probably also con- sible here, but one more deserves to be extensively known. siderable in the United Kingdom. See the articles Andes, It is the best application to chilblains, especially at first; CHILE, Mexico, Peru, Porosi
, for an account of the South but even after they break, it disposes them to heal. American mines; Austria, HUNGARY, SAXONY, &c., for When a solution of nitrate of silver is made, distilled those of Europe.
water should invariably be used. The neglect of this rule (Jacob's Inquiry into the Produchon and Consumption causes many of the solutions applied to the eye to be not of the Precious Metals, 2 vols., London, 1831; Humboldt's only useless, but hurtful. Oxide of silver has been recently New Spain ; Personal Researches, &c.; Ward's Mexico, strongly recommended as an antispasmodic, and not liable &c.)
to the objections which attach to the nitrate. P. C., No. 1362.
SILVER, GERMAN. [TUTENAG.]
vermin; but if taken internally it causes stupor and other SILVER-GRAIN. In making a horizontal section of narcotic symptoms; it should therefore be carefully distinthe trunk of any tree, a number of straight lines will be seen guished from the former. radiating from the central pith through the wood to the SIMARUBA'CEÆ, a natural order of plants belonging bark. These rays are called by botanists medullary rays or to the gynobasic group of polypetalous Exogens. The plates, and by persons who work on wood silver-grain. plants of this order are trees or shrubs, with alternate exThey are composed entirely of cellular tissue, which is of a stipulate usually compound leaves, and mostly without dots. compressed form, and thence called muriform, and often do the flowers are whitish-green or purple, on axillary or not consist of more than a single layer of cells, although in terminal peduncles, hermaphrodite, or occasionally unisexual. some trees, as Aristolochias, the layers are very nu- The calyx is 4 or 5 parted; petals four to five, twisted in merous. In longitudinal sections of the stem they give it a æstivation; stamens twice as many as the petals, arising remarkable satiny lustre, which constitutes the great beauty from the back of an hypogynous scale; ovary 4 to 5 lobed ; of some woods, as the plane and the sycamore. The great style simple; stigma 4 or 5 lobed ; fruit a drupe; seeds variety that is seen in the character of different woods ap- pendulous, exalbuminous, with a superior short radicle pears to depend on the nature of the silver-grain, for the drawn back within thick cotyledons. With one exception woody and vascular tissues do not present sufficient dif- they are all natives of Africa, India, and tropical America. ference to constitute any obvious peculiarity. Thius in the This order was formerly included under Rutaceæ, but their cultivated cherry the plates are thin, and their adhesion to the differences from that order appear to many of sufficient bark slight, so that a section of this wood has a pale, smooth, importance to constitute a separate family. A. de Jussieu homogeneous appearance: but in the wild cherry the silver- says, They are known from all Rutaceous plants by the grain is much thicker; it adheres closely to the bark, and coexistence of these characters, namely, ovaries with but one is arranged with great irregularity, so that this wood when ovule, indehiscent drupes, exalbuminous seeds, a membracut has a deeper colour, and a twisted, knotted, irregular nous integument of the embryo, and by the radicle being appearance. In the two species of oak the same kind of retracted within thick cotyledons. differences are observable. * In Quercus sessiliflora the rays The plants of this order are all intensely bitter. The are thin and distant from each other, so that when a wedge Quassia on this account is used in medicine. (QUASSIA.] is driven into the end of the trunk the plates of wood do not Simaruba versicolor is so bitter that no insects will attack readily break into each other ; but in Quercus pedunculata it; and when all other specimens of plants in dried colthe rays are hard, and are so close together that the wood lections have been attacked by Ptini, &c., specimens of may be split up without any difficulty. [STEM.]
this plant have been left untouched. The Brazilians use SILVIC ACID, a substance which with pinic acid an infusion of this plant in brandy as a remedy against the [PINIC ACID) constitutes the greater portion of colophony, bites of serpents. or common rosin. When this substance is digested in cold
b alcohol of specific gravity 0.833, the pinic acid dissolves, but the silvic acid remains insoluble in alcohol until it is boiled; on cooling, it separates in crystals of considerable size, the form of which, according to Unverdorben, is a
u rhombic prism terminated by four facets, but Laurent repre
sd sents it as an acute rhomboid, the edges of which are usually serrated.
ya Silvic acid melts below 212°; is insoluble in water, but dissolves readily in hot alcohol and in æther, and is precepitated by water; it is soluble also in all proportions in the volatile and fixed oils. Concentrated sulphuric acid dissolves and water precipitates it from the acid; by the action of nitric acid it is converted into another resinous acid when it has been precipitated from alcohiol by water; amnionia dissolves this acid readily, and the silvale of ammonia formed, as well as that of potash and of soda, is soluble in water; most silvates are however insoluble in it, but many of them are dissolved by alcohol and by ætler; the silvate of magnesia especially is taken up by alcohol; the silvates of silver and lead are colourless and insoluble in water.
Silvic acid may be regarded as an oxide of oil of turpentine; its composition, as stated by the chemists above named, is as follows: it will be observed that there is no great difference between them, but they do not agree as to its constitution:
Unverdorben. Laurent, Equivalents. Hydrogen 10:36 9.7 or 40
Quassia amara. Carbon 79.28
52 = 312 79.6 a, brauch, showing flowers and compound leaves; b, flower; c, stamens Oxygen 10:36 10'6
40 10.2 separated, attached to hypogynous scale ; d, stamens surrounding ovary; e
ovary seated on a stalk, to which the sta mers are attached.
392 100 SIMBIRSK, a government of Asiatic Russia, is situated SIMARU'BA is the bark of the root of the Simaruba between 52° and 57° N. lat., and between 42° 20' and 50° amara (Aublet), S. officinalis (of Dec. and . Pharm. Lond.'), 20' E. long. It is bounded on the north by Kasan, on the a tall tree, native of Guayana, and also of Jamaica, if east by Orenburg, on the south by Saratow and Pensa, and the tree found in that island be not a distinct species. on the west by Nischnei Novgorod, The area is 24,000 It is imported in bales containing pieces a foot or more in square miles. The surface is in general an undulating length, tolerably broad, and generally formed into rolls the plain, but on the right bank of the Volga there is a range whole length of the piece. Externally it is rough, warty, of hills, composed of clay, marl, limestone, and freestone, and has a dirty-yellow cuticle marked with transverse which rise to the height of 400 feet. The principal river ridges; the epidermis below this is of a whitish-yellow of this government is the Volga, which enters it from Kacolour. Internally smooth, with a greyish yellow colour. It san, about the middle of the northern frontier, and runs in is devoid of odour, but intensely bitter. Its chief constituents a direction nearly south to Stavropol, where it turns to the are quassite, resin, a volatile oil having an odour like ben. east; and there, after being joined by the Sok, coming zoin, ulmin, mucilage, and some salts. It is tonic and de- from Orenburg, it makes a semicircular bend, and at Sa mulcent in small doses, and therefore useful in the later mara turns due west, in which direction it proceeds as far stages of dysentery, but in larger doses it is emetic. The as the town of Sysran, when it again turns to the south. It bark of the root of Simaruba versicolor (St. Hilaire) is very is at this bend that the eminences on the Volga are highest, like that above described, and is used externally by the though they accompany the river in its whole course from Brazilians as a wash to ill-conditioned ulcers, and to destroy | north to south. Beyond the bend the surface of the country